Unit 2

Unit 2ReviewWhat was wrong with Daltons atomic theory?His atom had no subatomic particles, and he thought the atom was solid. He also thought all atoms of the same element were identical. This is wrong. Now we know about isotopes.Which of the scientists discovered the nucleus and discovered the fact that most of the atom is empty space?RutherfordWhich scientist placed the electrons in energy levels orbiting the nucleus? BohrWho came up with the plum pudding model of the atom?ThomsonState the law of definite proportions.A chemical compound contains the same elements in exactly the same proportions by mass regardless of the size of the sample. For example, NaCl always contains 39% sodium(Na) by mass and 61% chlorine(Cl) by mass.What is the atomic number of an element?The number of protons.Which of the subatomic particles has no charge?neutronWhat does the number 4 mean in the hyphen notation hydrogen-4?4 is the mass number, the number of protons plus neutrons.How many protons, neutrons, and electrons are in 13C ? 66 protons7 neutrons6 electronsWhat is the mass in grams of 3.50 moles of copper, Cu?3.50 moles Cu x 63.55 g Cu = 222 g Cu 1 mole CuHow many moles of Mg are in 12.15 g of Mg?12.15 g Mg x 1 mole Mg = 0.5000 mole Mg 24.31 g MgHow many moles of Pb are there in 1.50 x 1012 atoms of Pb?1.50 x 1012 atoms of Pb X 1 mole of Pb = 6.02 x 10 23 atoms of Pb

2.49 x 10-12 mole Pb